Model S Window Fogging

[3985734987]

My S is sure prone to fogging up and not being able to keep up with the vents. Here's a photo of a recent fog episode. Had been driving for 20 minutes, only floor vents on, exterior temp 28f. All of the sudden it starts pumping humid air and completely fogs up all windows. What would cause this? This is a big of an extreme cause, but it commonly fogs up and requires me to roll down the windows and dump all the humid air.

 

[zanary]

What I find (and maybe it' just me), is that you should just leave it on auto, and only adjust the temperature. If you start to mess with it manually then you may end up with fog. Also make sure that "Range Mode is Off", as that will also limit HVAC performance.

 

[ekendahl]

Assuming setting is on auto then you need to check if your AC is actually working as expected. Seem like it's not drying out the air before blowing it on the window.

 

[Ande]

It may be a AC issue, like a leak, if pressure is too low, AC compressor won't start.
It's sad that Tesla does not clearly tell you when/if that's an issue.

 

[Hugh Mannity]

My car does this every time the temp is below freezing. About 15 min into the drive the windshield fogs up and then clears again. Weird.

if it’s bad enough you can click the windshield defrost button and it un fogs within seconds.

 

[BCCA]

Turning on the front windshield defroster clears up this problem for me.

 

[maximizese]

A few things:

• You might have excessive moisture in your car (wet floor mats/carpet, respiration, recirculator on, etc).
• Have you tried both the A/C defroster and the heater defroster? The former should be quick to clear up your windshield, but if it doesn't your issue probably lies with your air conditioning system. It might be as simple as your desiccant bag needing replacement or it could be more complex like the A/C compressor or drain not working properly.

I hope you get this resolved and in the meantime perhaps you should keep an absorbent rag near by to wipe the window.

 

[CyberShy]

Turning on the front windshield defroster clears up this problem for me.

This. Auto does not “automatically” defog the windows. Auto only refers to maintaining the temperature. Usually heating goes low, cooling goes out the middle.

You have to put the air where it is needed or wanted.

 

[jpwe10]

MAKE SURE AIR RECIRCULATION IS TURNED 'OFF' (highlighted blue is on, white is off).

What is happening is the HVAC system is recirculating the water vapor you exhale, which causes the fogging after a few minutes of driving.

Problem solved.

 

[Alysashley79]

seems kind of silly but when was the last time you changed the cabin air filter? mine was doing this no matter what I did. I changed my cabin filter and haven’t had a problem since. (my temps are usually in the low 20’s in the am and we have snow in the ground at my home and is raining in town)

fog x also helps a little.

 

[Battpower]

MAKE SURE AIR RECIRCULATION IS TURNED 'OFF' (highlighted blue is on, white is off).

What is happening is the HVAC system is recirculating the water vapor you exhale, which causes the fogging after a few minutes of driving.

Problem solved.

If I have a fogging issue, recirc setting is the first thing I check. I'm sure that sometimes the heater settings have changed themselves - maybe related to what's saved in different profiles.

Sometimes even with recirc definitely off, if a/c has been on and shuts off (for whatever reason) I have found that condensation built up in a/c system gets 'blown' into cabin and windows fog up very quickly. In such cases turning a/c back on usually clears.

To stop using a/c I have found that having fan on high and windows open while driving clears out humidity.

 

[Barry]

My car does this every time the temp is below freezing. About 15 min into the drive the windshield fogs up and then clears again. Weird.

I've noticed the same thing, but it doesn't happen often. It's clear, then rapidly fogs up, and clears just as quickly when defroster is turned on. Never have seen anything like this in any other car. FWIW, where I live, humidity is usually in the 20% range.

 

[Hugh Mannity]

I've noticed the same thing, but it doesn't happen often. It's clear, then rapidly fogs up, and clears just as quickly when defroster is turned on. Never have seen anything like this in any other car. FWIW, where I live, humidity is usually in the 20% range.

yeah I’m in Alberta. Very low humidity here too.

 

[Ewiz]

My S is sure prone to fogging up and not being able to keep up with the vents. Here's a photo of a recent fog episode. Had been driving for 20 minutes, only floor vents on, exterior temp 28f. All of the sudden it starts pumping humid air and completely fogs up all windows. What would cause this? This is a big of an extreme cause, but it commonly fogs up and requires me to roll down the windows and dump all the humid air.

I have a 2015 model S does the same thing, It’s a love-hate relationship, first car I’ve ever had this problem with. Tesla service center will not fit my front drive unit whine, noise, rear drive unit clunk, many issues like this make me want to get rid of the vehicle.

 

[islandbayy]

1: Make sure Recirculation is OFF.
2: Keep FAN SPEED AT OR BELOW 9. Turning Fan speed to 10 or 11, will automatically re-activate recirculation, weather it shows it active or not, weather you selected recirculation or not.
Done.

With the above, you should almost never need the AC in the winter to keep the windows fog free.